a-mav™ anterior motion segment replacement

Conditions: Spinal Diseases

Summary: the purpose of this clinical trial is to collect safety and effectiveness data concerning the a-mav™ anterior motion segment replacement device as a method of treating patients with lumbar degenerative disc disease at one level from l4-s1. overall success will be the primary clinical endpoint.

for this clinical trial, there is only one treatment group- patients receiving the a-mav™ anterior motion segment replacement via an anterior surgical approach in the lumbar region of the spine from l4-s1.

Eligibility criteria:
inclusion criteria: * has back and/or radicular pain with degeneration of the disc as confirmed by patient history, physical examination, and radiographic studies with one or more of the following factors: * instability as defined by \> 5° angulation * osteophyte formation of facet joints or vertebral endplates * decreased disc height, on average by \>2mm, relative to the next adjacent vertebral segment * scarring/thickening of ligamentum flavum, annulus fibrosis, or facet joint capsule * herniated nucleus pulposus * facet joint degeneration/changes * vacuum phenomenon * has single-level symptomatic degenerative involvement from l4-s1 requiring surgical treatment * has intact facet joints at the involved vertebral levels documented by ct and/or mri * has preop oswestry score≥30 * has preop back pain score ≥8 * age 18 to 70 yrs, inclusive and is skeletally mature * has not responded to non-operative treatment for 6 mos * if child-bearing potential, patient is non-pregnant, non-nursing, and agrees not to become pregnant for 1 yr after surgery * is willing and able to comply with the study plan and sign the patient informed consent form exclusion criteria: * has primary diagnosis of a spinal disorder other than ddd at involved level * had previous anterior lumbar spinal surgery at involved level * had previous posterior lumbar spinal fusion surgical procedure at involved level * had prior posterior lumbar surgery resulting in significant muscle/ligament morbidity, not including facet saving techniques * requires surgical intervention at more than 1 lumbar level * has severe pathology of facet joints of involved vertebral bodies * has facet arthritis or any posterior element insufficiency * has spondylolisthesis * has mid-sagittal stenosis of \<8mm, based on remaining canal diameter * has rotatory scoliosis at involved level * has lumbar scoliosis with \>11° sagittal plane deformity * had previous trauma to l4, l5, or s1 levels in compression or burst * meets any of the following criteria: previous diagnosis of osteoporosis, osteopenia, or osteomalacia; postmenopausal non-black female over 60 yrs of age and weighs less than 140 pounds; postmenopausal female that has sustained a non-traumatic hip, spine or wrist fracture; male over age 60 that has sustained a non-traumatic hip or spine fracture. if yes to any of these, a dexa scan is required. if level of bmd is -3.5 or lower or -2.5 or lower with vertebral crush fracture, the patient is excluded * had previous lumbar spinal fusion at adjacent level * bone growth stimulator use in spine * has obesity defined by bmi greater than or equal to 40 * has arachnoiditis * has a non-contained or extruded herniated nucleus pulposus with acute nerve root compression * has condition that requires postop medications that interfere with bone metabolism, such as chronic steroid use or prolonged use of non-steroidal anti-inflammatory drugs, excluding routine perioperative, non-steroidal anti-inflammatory drugs. does not include low dose aspirin for prophylactic anticoagulation * has overt or active bacterial infection, either local or systemic and/or potential for bacteremia * has presence or prior history of malignancy (except for basal cell carcinoma of skin) * has documented metal allergy, titanium alloy intolerance or cobalt-chrome-molybdenum alloy * is mentally incompetent. if questionable, obtain psych consult * has a waddell signs of inorganic behavior score of 3 or greater * has chronic or acute renal and/or hepatic failure or prior history of renal and/or hepatic parenchymal disease * is prisoner * is pregnant * is an alcohol and/or drug abuser as defined by currently undergoing treatment for alcohol and/or drug abuse * has history of autoimmune disease * has received treatment with an investigational therapy within 30 days prior to implantation surgery or treatment is planned during 24 months following the implantation surgery * has history of any endocrine or metabolic disorder known to affect osteogenesis * has any disease that would preclude accurate clinical evaluation

Keywords: lumbar degenerative disc disease at one level from l4-s1